Backrud, M;
Tjulin, A;
Vaivads, A;
Andre, M;
FAZAKERLEY, AN;
(2005)
Interferometric identification of ion acoustic broadband waves in the auroral region: CLUSTER observations.
Geophysical Research Letters
, 32
(21)
, Article L21109. 10.1029/2005GL022640.
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Abstract
We determine the phase velocity and k vector for parallel and oblique broadband extremely low frequency, ELF, waves on nightside auroral magnetic field lines at altitudes around 4.6 R_E. We use internal burst mode data from the EFW electric field and wave instrument onboard the Cluster spacecraft to retrieve phase differences between the four probes of the instrument. The retrieved characteristic phase velocity is of the order of the ion acoustic speed and larger than the thermal velocity of the protons. The typical wavelength obtained from interferometry is around the proton gyro radius and always larger than the Debye length. We find that in regions with essentially no suprathermal electrons above a few tens of eV the observed broadband waves above the proton gyro frequency are consistent with upgoing ion acoustic and oblique ion acoustic waves.
| Type: | Article |
|---|---|
| Title: | Interferometric identification of ion acoustic broadband waves in the auroral region: CLUSTER observations |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1029/2005GL022640 |
| Publisher version: | http://dx.doi.org/10.1029/2005GL022640 |
| Language: | English |
| Additional information: | Copyright 2005 by the American Geophysical Union |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics |
| URI: | https://discovery.ucl.ac.uk/id/eprint/157261 |
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